Claims:1. A central electrode (10) for a sparkplug (12), said 5 central electrode
(10) provided within the insulator assembly (14) of said sparkplug
(12), said central electrode (10) comprising
- a hollow portion (16); and
- firing tip portion (18),
10 said hollow portion comprising an evaporator section (16a) and a
filler section (16b);
said firing tip portion (18) is the part of the central electrode (10)
extending from said insulator assembly (14) to form a firing tip (16)
of said central electrode.
2. The central electrode (10) as claimed in claim 1, wherein said filler
section (16b) is filled with a fluid having low melting point.
3. The central electrode (10) as claimed in claim 2, wherein said low
melting point fluid may be at least one chosen from a group of low
20 melting points fluid such as sodium, potassium, cesium and the like.
4. The central electrode (10) as claimed in claim 1, wherein said
evaporator section (16a) comprises a wick structure formed by a
sintering process.
5. A sparkplug (12) comprising a ground electrode (22) and a central
electrode assembly, said ground electrode (22) welded on metal
housing (23) mounted on an insulator assembly (14), said metal
housing (23) having external threads (24) for fitting said sparkplug
on an engine, said central electrode assembly comprising 5 a central
electrode (10), characterized in that said central electrode (10)
comprising
- a hollow portion (16); and
- firing tip portion (18),
10 said hollow portion (16) of said central electrode located within said
insulator assembly (14) in a manner such that the hollow portion
(16) is aligned with the external threads (24) of said metal housing
(23) so as to form a heat transfer path (26) from said firing tip
portion (18) to said hollow portion (16) to said external threads
(24). , Description:A sparkplug is disclosed. The sparkplug (12) comprises a ground
electrode 22 and a central electrode assembly. The ground 5 electrode 22 is
mounted on an insulator assembly 14. The ground electrode 22 is welded
to metal housing 23 which has external threads 24 for fitting the sparkplug
on an engine. The central electrode assembly comprising a central
electrode 10. The sparkplug is characterized in manner such that the
10 central electrode 10 comprises a hollow portion 16; and firing tip portion
18. The hollow portion 16 of the central electrode located within the
insulator assembly 14 in a manner such that the hollow portion 16 is
aligned with the external threads 24 of the metal housing 23 so as to form
a heat transfer path 26 from the firing tip portion 18 to the hollow portion
15 16 to the external threads 24.